GROWTH-STUDIES OF (AL,GA,IN)AS ON INP BY MOLECULAR-BEAM EPITAXY

We have investigated the influence of growth temperature and growth interruptions on the optical properties of (Al,In)As, (Ga,In)As and (Al,Ga,In)As lattice-matched to InP substrates. Heterostructures and bulk material samples were analyzed by photoluminescence, X-ray spectroscopy, transmission electron microscopy and optical microscopy. The best optical properties are achieved at different growth temperatures, depending on the material composition. This temperature varies between 460-degrees-C for (Ga,In)As and 530-degrees-C for (Al,In)As. Photoluminescence studies of quantum well (QW) samples show that heterointerfaces grown from (Ga,In)As to (Al,In)As are very sensitive to growth stops, while there is no significant influence if the growth stop is made after growth of (Al,In)As. Laser structures with three QWs made from that material system reach threshold current densities for infinitely long cavities as low as 120 A/CM2 per QW for an emission wavelength of 1.7 mum and 260 A/cm2 per QW for 1.3 mum.